1. Field of the Invention
The invention relates to a slide fastener.
It relates more particularly to a slide fastener of the type having two strips, each of which is provided with a fastening device along one of its edges, and having a slider that slides along the edges of the strips to control, during a movement of the slider in a locking direction, the locking of the fastening devices of the two strips and, during a movement of the slider in an unlocking direction, the unlocking of the fastening devices of the two strips.
2. Description of Background and Relevant Information
Fastening devices can take various forms. They can be two series of teeth, each arranged on a strip in an offset manner to be engaged one in the other in order to lock the two strips, thereby constituting a fastener of the “zipper” type. They can also be two complementary continuous sections of the male-female type whose engagement or disengagement is controlled by the slider. In certain slide fasteners, the fastening means can be made in the form of two spiral elements that are connected to each of the strips and that are nested one in the other. All of these types of slide fasteners are well known to those persons skilled in the art.
The slider acts on the fastening devices in one direction to bring them close together (i.e., the “locking direction,” thus causing the cooperation of the fastening devices and their locking), and in the other direction to separate them (i.e., the “unlocking direction,” thus causing the unlocking of the fastening devices of the two strips). The slider therefore slides along the length of the slide fastener while being guided by the fastening devices.
These types of slide fasteners are used in numerous applications, but specifically to achieve a resealable opening between two pieces of flexible material, for example, in garments. It is advantageous for the handling of the slide fastener to be as easy as possible, i.e., for the sliding of the slider along the length of the slide fastener to be done with a minimum of effort.
However, there is then the risk that the slider may become displaced along the length of the slide fastener in the unlocking direction under the sole effect of interfering forces sustained by the slide fastener. This is particularly true with respect to garments where slide fasteners are subject to alternative deformations of the pieces of fabric that they bring close together. This is all the more true when the slide fastener is arranged to be vertical in use with an upper locking position, as gravity then acts on the slider in the direction for unlocking the slide fastener.
Systems for locking the slider in a given position have already been proposed. Thus, there are slide fasteners in which the slider has a movable pull tab adapted to enable one to grip the slider, this pull tab being further provided with a blocking member that, in a position for blocking the pull tab, cooperates with the means for fastening the slide fastener in order to block the slider. For this blocking to be effective, however, it is imperative that the pull tab remain in its blocked position, which is not always guaranteed. Applications are also known in which a strip of fabric is provided which is fixed to one side of the slide fastener and which has anchoring means (for example, self-gripping strips of the Velcro® type, i.e., hook and loop fastening elements), such that it is possible to attach the strip of fabric across the longitudinal direction of the slide fastener. The strip of fabric, once positioned in this manner, thus prevents the slider from being displaced in an unlocking direction. Such a system nonetheless requires one to remember to position the strip of fabric after each closure of the slide fastener. In addition, it is sometimes difficult to unfasten the strip of fabric when one wants to manipulate the slider in the unlocking direction.